Circuit arrangement for rocket launchers

ABSTRACT

A rocket launcher firing control circuit in which a series of rockets are fired either individually or automatically in sequence under the control of a mode selector switch control the mode of operation of a clock pulse generator, a counter counting the generator pulses and a decoder controlled by the counter output for firing the detonator caps of a series of rockets in sequence via thyristors connected in parallel to a power source. The control electrode of each thyristor is connected to a separate output of the decoder and the generator is controlled by a digital control unit so that the operation of the system is not impaired by the presence of a faulty rocket detonator unit.

United States Patent 1 [111 3,748,955 Gatermann et al. 1 July 31, 1973[54] CIRCUIT ARRANGEMENT FOR ROCKET 3,306,208 2/1967 Bergey et al.102/702 R LAUNCHERS 3,312,869 3/1967 Werner 317/80 3,316,451 4/1967Silbermannm 317/80 InvenwrSI Willi Gatermann; Rolf g 3,468,255 9/1969Stryker 102/702 R Hinder-k Mudder; Lens-Dietrich 3,504,189 3/1970McHenry.. 89/L814 X Thieme, all of Wedel/Holstein; 3,603,844 9/1971Fritz 102/702 A Herbert Sedlacek, Hamburg-Rissen; Uwe Weers, Elmshorn;Heinz Hermes wad/Holstein a" of Primary Examiner-Samuel W. Engle GermanyAttrney-George H. Spencer et al.

[73] Assignee: Licentia Patent-Verwaltungs-G.m.b.H., Frankfurt am Main,Germany ABSTRACT [22] Filed: Sept 197.1 A rocket launcher firing controlcircuit in which a se- [21] Appl. No.: 182,106 ries of rockets are firedeither individually or automatically in sequence under the control of amode selector switch control the mode of operation of a clock pulseForelgn Apphcanon Pnonty Data generator, 3 counter counting thegenerator pulses and Sept. 18, Germany P a decoder controlled thecounter for firing the detonator caps of a series of rockets in sequencevia 89/1314, 102/702 R, 317/80 thyristors connected in parallel to apower source. The control electrode of each thyristor is connected to aFleld 0 Search eparate output of the decoder and the generator is102/70-2 A, R; 317/ controlled by a digital control unit so that theoperation of the system is not impaired by the presence of a faultyReferences Cmd rocket detonator unit.

UNITED STATES PATENTS 3,598,015 8/1971 Delistovich et al. 89/ 1.814 2Claims, 2 Drawing Figures ELECTRON/C 9 hl([:j-- fi \I I, /7 I l DIG/TEALCONTROL i IO UNIT 0 C CLOCK PULSE l 1 CURRENT GENERATOR SENSOR BINARYCODED 6 DEC/MAL COUNTER DCODER i5 CICUIT ARRANGEMENT FOR ROCKETLAUNCHERS BACKGROUND OF THE INVENTION The present invention relates to acircuit arrangement for rocket launchers, particularly for triggeringdetonator caps in such a manner as to permit firing rockets either insequence or individually.

The firing of a rocket propelling charge is initiated by a so-calleddetonator cap which is disposed in the charge. Such detonator capcontains a heating wire which is enclosed by a quantity of powder. Whenthe heating wire is heated, the quantity of powder is ignited so thatthe outer shell of the detonator cap explodes and fires the rocketpropellant charge.

With a plurality of rockets arranged next to one another to constitute arocket battery or batteries it is necessary, for example, that therockets be fired either one after the other at certain time intervals,i.e., in sequence, or that each individual rocket be fired separately.To meet this requirement, an electromagnetic circuit arrangement isknown which is operated by a stepping switch mechanism. The entirecircuit arrangement is built into the rocket starting device.

This circuit arrangement has the drawback that the presence of a shortcircuit in one of the firing lines leading to one rocket prevents thefiring of the detonator caps which are connected to the firing linesfollowing the short-cireuited line.

Furthermore, it is possible for the mechanical follower in the steppingswitch mechanism to malfunction during an acceleration of the circuitarrangement. Such an acceleration may occur, for example, when therocket launchers are mounted on airborne bodies.

A soiling of the contacts of the switching mechanism is also verydetrimental to perfect operation.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide a circuit arrangement which eliminates theabove-mentioned drawbacks.

A further object of the invention is to assure faultfree firing of aplurality of rockets either in sequence or individually from launchersdisposed on the ground or from those mounted on airborne bodies.

These and other objects are accomplished according to the presentinvention by the provision of means which initiate the functionssequential firing or individual firing under the control of anoperational mode selection switch and a firing key and through theapplication of a supply voltage, and which assure the automatic sequenceof the firing process even when there is a fault in one or more of thefiring lines.

The supply voltage can be switched, during the sequential firingoperation, from an electronic switch to a plurality of thyristors insuccession, a clock pulse generator controlling the electronic switch aswell as the thyristors, the latter via a counter and a decoder. Theclock pulse generator provides for this purpose a frequency which has avarying value.

For the "individual firing" operation, the clock pulse generator, whichsimultaneously controls a counter and an electronic switch, is switchedby means of a digital control unit to produce a high clock pulsefrequency. This high clock pulse frequency continues until a cur rentsensor locates a closed firing circuit and furnishes a signal to thedigital control unit. Then the clock pulse generator switches back tothe original frequency, the firing voltage is applied to the thryistorof the closed firing circuit and the digital control unit furnishes astop signal to the clock pulse generator when the thyristor has fired.The digital control unit will not furnish a stop signal to the clockpulse generator when there is a permanent short circuit in one of thefiring lines.

The advantage of the present invention is that no memory elements areprovided in the circuit arrangement. Thus it results that only theperfect detonator cap which is next in line in the given sequence isfired, regardless of the presence of a short circuit or an interruptionin the preceding firing line. Even with a short circuit or aninterruption in one firing line, the series firing and individual firingoperations are perfomied. The circuit arrangement can also be built intothe rocket launching devices in place of the previously employedelectromagnetic circuit arrangement.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a circuit diagram of onepreferred embodiment of the present invention.

FIG. 2 illustrates one embodiment of a appliedclock pulse generator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The firing circuit of theillustrated embodiment includes a firing unit 1 in which a plurality of,e.g., l0, thyristors are connected together, only three thyristors 2, 3and 4 being shown. The outputs of the thyristors 2, 3 and 4 areconnected in a standard manner to heat ing wires belonging to detonatorcaps (not shown). The control inputs of the thyristors are conductivelyconnected to a clock pulse generator 7 via a decoder 5 and a binarycoded decimal counter 6, the clock pulse generator 7 being fed by thesupply voltage for the system.

Two control inputs of the clock pulse generator 7 are conductivelyconnected to two outputs of a digital control unit 8. One of theconnecting lines is required for switching the frequency of the clockpulse sequence and the other line is required to switch off the clockpulse generator 7.

The digital control unit 8 has a total of three inputs: the first inputis connected to the output of the clock pulse generator 7; the secondinput is electrically connected to an operational mode selector switch9; and the third input with the signal output of a current sensor 10.

The supply voltage inputs of the thyristors 2, 3, 4, etc., areconnected, via the operating circuits of current sensor 10 and anelectronic switch 11, to a firing key 12 through which the supplyvoltage can be applied to the electronic switch 1 l as well as to theclock pulse generator 7. The control input of the electronic switch 111is in electrically conductive connection with the output of the clockpulse generator 7.

The mode of operation of this circuit arrangement will first bedescribed for the sequential firing function,

.in which the operational mode selection switch 9 has the illustratedposition and the supply voltage is applied, via electronic switch illand current sensor 10, in succession to thyristors 2, 3, and 4 and thusalso to their associated detonator caps.

The automatic firing process of'thyristors 2, 3, and 4 is initiated bythe actuation of the firing key 12 and continues as follows:

First clock pulse generator 7 starts running freely and feeds pulses atits normal clock pulse frequency to the BCD counter 6. The decoder 5converts the BCD code to a code and applies in succession with eachcount a control pulse to the control input of each successive thyristor2, 3, and 4, etc., each pulse having a duration of 20 msec. The timebetween the firing of two adjacent thyristors is 25 msec, so that inthis example with 10 detonators all of the thyristors will have beenpulsed once in a period of 250 msec.

Together with the timing of clock pulse generator 7, the electronicswitch 11 is controlled in parallel with the control pulses and thesupply voltage is applied to the voltage inputs of the thyristors 2, 3,and 4, etc., in synchronism with the control pulses. However, it will beonly the thyristor which receives a control voltage at its grid and asupply voltage at its voltage input which will be fired. This ANDrequirement presence of the supply voltage and the grid pulse at thesame time must always be met to fire a detonator cap.

In order to achieve the required firing sequence period of 25 msec inoperation, the clock pulse generator must be so designed that it emits aclock pulse train with pulses and pulse intervals of differentdurations. For a time period of 20 msec the clock pulse generator 7emits a signal representing a binary l which closes the electronicswitch 11, i.e., renders it conductive, and simultaneously serves as acounting pulse for the BCD counter 6. A firing pulse is derived from thecounter output by decoder 5. The counter 6 is set to produce an outputsignal representing a logic at each switching on by the firing key 12 sothat a continuous firing sequence from thyristor 2 to thyristor 4 isalways assured.

If it should occur that the detonator cap in one of the rockets burnsinto a short circuit so that the launch can not be initiated, thecurrent to that cap is interrupted after approximately 20 msec by thecircuit arrangement itself, and after the current interruption there isa pause of 5 msec'until the next detonator cap is fired. The circuitarrangement acts in the same manner when the input leads to one or moredetonator caps have a short circuit to ground. If, however, a firingline is broken, the effect on the circuit arrangement will be the sameas if the detonator cap had already been fired.

For the individual firing function, the circuit arrangement is to fireonly a single thyristor and launch only one rocket. For this purpose,the operational mode selector switch 9 in the rocket launching device ismoved into the position shown in the drawing in dashed lines to connectone input of control unit 8 to ground. With this switching arrangementthe clock pulse frequency of the clock pulse generator 7 is switched bymeans of the digital control unit 8 to a higher value. As for the caseof sequential operation, counter 6 is controlled to effect a countsimultaneously with the closing of electronic switch 11.

If several detonator caps have been fired, the clock pulse generator 7continues at the higher clock pulse frequency until the current sensordetects a closed firing circuit. The current sensor 10, when it hasrecognized a closed firing circuit, furnishes a signal to the digitalcontrol unit 8 which switches clock pulse generator 7 back to theoriginal frequency. If the current sensor 10 indicates, within a periodof 20 msec, a current interruption in the recognized firing circuit,i.e., the thyristor associated with this firing circuit is being firedso that there now is an open firing circuit, the digital control unit 8additionally furnishes a stop signal to clock pulse generator 7. Thestop signal prevents a further switching to the next-following firingcircuit. The next firing of a thyristor can then take place only throughrenewed depression of the firing key 12 so that counter 6 is set back tozero and the next closed firing circuit is located in a very short time.

If a short circuit is present in a line in the form of a previouslyfired detonator cap, or if there is a line short circuit to ground, thedigital control unit 8 will not furnish a stop signal due to thepresence of a continuous short circuit'current. Rather, as'in'sequential'operation, the current is switched off after 20 msec and after afurther 5 msec it is switched to the next firing circuit. This processis automatically continued until a properly functioning firing line hasbeen found and the firing takes place as planned. A firing circuit whichhas been interrupted by a defective firing line can be considered to bean open firing line. Line a in FIG. 2 serves to transmit a stop signalfrom the digital control unit 8 to the clock pulse generator 7. On theother hand, the signal transmitted by line b to the clock pulsegenerator 7 causes a change-over of the frequency of the clock pulsegenerator 7 from Slow to Quick" or vice versa. The signal delivered bythe clock pulse generator 7 through line 0 serves to control the binarycoded decimal counter 6 of the electronic switch 11 and line b in theindividual as well as in the sequential firing operational mode.

In the operational mode Sequential firing (switch 9 in the position asshown), there is a L-signal at the inverter located in the left upperpart of the digital control unit 8, whereas a O-signal is present at theinverter output. A O-signal is then continuously applied to line a. Inthis operational mode no stop signal can influence the clock pulsegenerator 7. The L-signal deriving from the operational mode selectorswitch 9 results in a continuous O-signal'at the output of the upperright Andgate of the digital control unit 8. Thus the current sensor 10cannot effect line b consequently, the signal on line b follows thesignal of line 0.

In the operational mode Individual firing (switch 9 shown in-theposition marked by dotted lines), there is a continuous L-signal at theleft input of the left lower And-gate of the digital control unit 8because of the negation by the inverter. Thus the signal on line a canfollow the signal output of the current sensor 10. The clock pulsegenerator 7 is not stopped if the current sensor 10 should cause aL-signal. The stopping only takes place if this signal returns to Zero.As long as the current sensor 10 has no L-signal, the line b has aO-signal. The clock pulse generator 7 operates with this signal in thehighest pulse frequency. When a L- signal is present, the clock pulsegenerator 7 opei'ates with the lowest frequency. The feedback to theclock pulse generator 7 through line 0 in the operational modeIndividual firing" is without effect on the signal on line b The clockpulse generator 7 shown in FIG. 2 has 3 inputs a, b and c (as shown inFIG. 1) and the power supply. The control of the input b has alreadybeen described together with the digital control unit 8. In case of aL-signal on line b, the transistor 13 is turned on.

In order to charge the capacitor 14, in this case it is only theresistor 15 that can become effective. A slow pulse sequence is producedat the unijunction transistor. When line b has a O-signal the resistor17 acts in parallel to resistor and furnishes the necessary chargingresistance. Thus the frequency of the pulse sequence of the unijunctiontransistor 16 is increased. The output signal of the transistor 16 isfed into a flipflop 18, the output signal of which appears on line 0.The signal of line c is fed back by the digital control unit 8 throughline b of the clock pulse generator 7. In the operational modeIndividual firing the line a has a L-signal, when a L-signal appearsthat is released by the current sensor 10. Since a stop of the clockpulse generator 7 may only take place after appearance of a O-signal onthe line a following the L-signal, this L- signal must first beconverted in the clock pulse generator 7 by an inverter 19, since thesubsequent flip-flop 20 only operates when the side of the pulse ispositive. The flip-flop 20 can then pass the information at its input Don the positive pulse side to its output Q. Owing to the couplingbetween the clock pulse generator 7 and the current sensor 11, at thistime only a L- signal can appear at the input D of the flip-flop 20. Incase of a L-signal at the output of the flip-flop 20, the transistor 21is turned on. An additional charging of the capacitor 16 is avoided.

The components not designated in FIG. 2 only serve to adjust theoperating point and to compensate the temperature of the components.

In one embodiment of the present invention it is proposed to encase thecircuit arrangement in silicon rubber to form a completely encapsulatedunit. It is in this case advisable to dispose the outputs so that theyare protected against short circuits and the inputs against changes ofpolarity. Such a case unit can easily be installed in rocket launchingdevices.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations, and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

We claim:

1. In a device for launching a plurality of rockets each containing adetonator device arranged in a firing circuit, a circuit for controllingthe firing of the detonator devices, comprising, in combination: afiring key connected for applying firing energy to the detonatordevices; mode selector switch means connected for controlling the modeof operation of said circuit and switchable between a first position inwhich it causes all previously unfired detonator devices to be fired insequence when said key is actuated and a second position in which itcauses one detonator device to be fired each time said key is actuated,successive actuations of said key causing successive detonator devicesto be actuated; and control circuit means connected between said key,said mode selector switch means and the detonator devices for sustainingthe selected mode of operation of said circuit despite malfunctions inthe firing current path of one or more of the detonator devices, saidcontrol circuit means including: a plurality of thyristors each havingone main electrode arranged to be connected to a respective detonatordevice; an electronic switch one side of which is connected to said keyand the other side of which is connected in common to the other mainelectrodes of all of said thyristors; a clock pulse generator connectedto control the operation of said electronic switch; a counter anddecoder connected between said generator and the control electrodes ofsaid thyristor; a digital control unit connected between said selectorswitch means and said generator for controlling the operation of saidgenerator; and a current sensor connected for sensing the currentconducted by said electronic switch and producing an output signal whenit senses a current level corresponding to that drawn by an operativefiring circuit, said sensor being connected to apply its output signalas an input to said control unit; wherein when said switch means is inits said first position, said pulse generator produces an output at afirst frequency, composed of pulses whose duration is different from theinterval between pulses, which causes each of said thyristors to betriggered into conduction in sequence by the output signals from saiddecoder, and said control unit is responsive to the switching of saidselector switch into its said second position for causing said generatorto produce an output at a second frequency higher than said firstfrequency upon the actuation of said key and until said sensor producesits output signal, to then produce an output at said first frequency tofire an operative detonator device, and to then stop.

2. An arrangement as defined in claim 1 wherein when said selectorswitch means is in its said second position, said control circuit isarranged to maintain the operation of said generator at said firstfrequency when the output signal from said sensor is due to ashortcircuited firing circuit and until a detonator device in anoperative firing circuit is fired.

v UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,748,955 Da e July 31st, 1973 Willi Gatermann, Rolf Slirgel, HinderkMudder, fl Klaus-Dietrich Thieme, Herbert Sedlacek, Uwe Weers and HeinzHermes It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

In the heading of the patent, change the fourth inventor's name to-Klaus-Dietrich Thieme.

Signed and sealed this 18th day of December 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. I RENE D. TEGTMEYER Attesting Officer ActingCommissioner of Patents FORM PO-105O (10-69) USCOMM-DC 603 76-P69 Q U.S.GOVERNMENT PRINTING OFFICE "I, 0-366-3,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 748955 Dated July 31st, 1973 Willi Gatermann, Rolf Sjrgel, Hinderk Mudder,Invent0r(8) Klaus-Dietrich Thieme, Herbert Sedlacek, Uwe Weers and HeinzHermes It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

In the heading of the patent, change the fourth inventors name to--Klaus-Dietrich Thieme-.

Signed and sealed this 18th day of December 1973.

(SEAL) Attest:

EDWARD N.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer ActingCommissioner of Patents FORM PO-1050 (10-69) USCOMM-DC GOING-P69 t U.5.GOVERNMENT PRINTING OFFICE I9! 0-3E6-83l.

1. In a device for launching a plurality of rockets each containing adetonator device arranged in a firing circuit, a circuit for controllingthe firing of the detonator devices, comprising, in combination: afiring key connected for applying firing energy to the detonatordevices; mode selector switch means connected for controlling the modeof operation of said circuit and switchable between a first position inwhich it causes all previously unfired detonator devices to be fired insequence when said key is actuated and a second position in which itcauses one detonator device to be fired each time said key is actuated,successive actuations of said key causing successive detonator devicesto be actuated; and control circuit means connected between said key,said mode selector switch means and the detonator devices for sustainingthe selected mode of operation of said circuit despite malfunctions inthe firing current path of one or more of the detonator devices, saidcontrol circuit means including: a plurality of thyristors each havingone main electrode arranged to be connected to a respective detonatordevice; an electronic switch one side of which is connected to said keyand the other side of which is connected in common to the other mainelectrodes of all of said thyristors; a clock pulse generator connectedto control the operation of said electronic switch; a counter anddecoder connected between said generator and the control electrodes ofsaid thyristor; a digital control unit connected between said selectorswitch means and said generator for controlling the operation of saidgenerator; and a current sensor connected for sensing the currentconducted by said electronic switch and producing an output signal whenit senses a current level corresponding to that drawn by an operativefiring circuit, said sensor being connected to apply its output signalas an input to said control unit; wherein when said switch means is inits said first position, said pulse generator produces an output at afirst frequency, composed of pulses whose duration is different from theiNterval between pulses, which causes each of said thyristors to betriggered into conduction in sequence by the output signals from saiddecoder, and said control unit is responsive to the switching of saidselector switch into its said second position for causing said generatorto produce an output at a second frequency higher than said firstfrequency upon the actuation of said key and until said sensor producesits output signal, to then produce an output at said first frequency tofire an operative detonator device, and to then stop.
 2. An arrangementas defined in claim 1 wherein when said selector switch means is in itssaid second position, said control circuit is arranged to maintain theoperation of said generator at said first frequency when the outputsignal from said sensor is due to a short-circuited firing circuit anduntil a detonator device in an operative firing circuit is fired.